15 Terrible Things That Happen If You Eat Too Much Sugar

Even one pack of M&M's may be more than you should eat in a
day, newly drafted guidelines from the World
Health Organization suggest.

The WHO used to recommend that you get no more than 10% of your
daily calories from sugar, but now they're considering lowering
that to 5%. For an average, healthy adult, that would mean 25
grams, or about six teaspoons of sugar per day. (That's a little
less than what you'd get from 10 Hershey's Kisses. A single can
of Coke has 39 grams of sugar.)

A teaspoon of sugar in your coffee or a half cup of ice cream
won't kill you — all things in moderation — but the average sugar
intake in the U.S. is 22 teaspoons per person per day. That's almost four
times as much as the WHO's new guidelines suggest is healthy.

People have been sounding warnings about the dangers of too much
sugar for a long time. As early as 1957, John Yudkin, a professor
of nutrition at Queen Elizabeth College in London, began arguing that when it came to heart
disease and other chronic ailments, sugar — not fat — was the
culprit.

So what happens if you eat too much sugar? Here's a depressing
rundown.

1. Cavities

Trust your dentist on this one: Sugar is such an enemy to dental
health that one study way back in 1967 called it the
"arch criminal" behind cavities. The connection between sugar and
cavities is perhaps the best established. "Tooth decay occurs
when the bacteria that line the teeth feed on simple sugars,
creating acid that destroys enamel," Anahad O'Connor explains at The New York Times. Because acid is a
key culprit, sour candies are especially nefarious.

2. Insatiable hunger

Leptin is a hormone that lets your body know when you've had
enough to eat. In people who develop leptin resistance, this "I'm
full" signal is never received, presenting a major obstacle for
weight control.

Some studies have raised the possibility that
leptin resistance may be a side effect of obesity, not a
contributing cause. But research in rats suggests that
overconsumption of fructose can directly lead to
higher-than-normal levels of leptin, which can reduce your body's
sensitivity to the hormone. Removing fructose from the rats'
diets generally reversed those effects.

3. Weight gain

Other than adopting a completely sedentary lifestyle, there are
few routes to packing on the pounds that work as swiftly and
assuredly as making large amounts of added sugars a staple of
your daily diet. Sugary foods are full of calories but will do
little to satiate your hunger. A 2013 review of 68 different
studies found "consistent evidence that increasing or decreasing
intake of dietary sugars from current levels of intake is
associated with corresponding changes in body weight in adults."
Want to lose weight? Cutting your sugar intake is a good place to
start.

4. Insulin resistance

When you eat a lot of high-sugar meals — donuts for breakfast,
anyone? — it can increase your body's demand for insulin, a
hormone that helps your body convert food into usable energy. When insulin
levels are consistently high, your body's sensitivity to the
hormone is reduced, and glucose builds up in the blood. Symptoms of insulin resistance can include fatigue,
hunger, brain fog, and high blood pressure. It's also associated
with extra weight around the middle. Still, most people don't
realize they are insulin resistant until it develops into
full-blown diabetes — a much more serious diagnosis.

5. Diabetes

One study that followed 51,603 women between 1991 and 1999 found
an increased risk of diabetes among those who consumed more
sugar-sweetened beverages — that's soda, sweetened ice tea,
energy drinks, etc. And a massive review of previous research
involving 310,819 participants supported this result, concluding
that drinking lots of soda was associated not just with weight
gain but with the development of type 2 diabetes.

Portion control may be especially crucial when it comes to sugar.
"Duration and degree of sugar exposure correlated significantly
with diabetes prevalence ... while declines in sugar exposure
correlated with significant subsequent declines in diabetes
rates" — even after controlling for other socioeconomic and
dietary factors, concluded a 2013 study of eating habits and
diabetes prevalence in 175 countries.

6. Obesity

Obesity is one of the most-cited risks of excess sugar
consumption. Just one can of soda each day could lead to 15
pounds of weight gain in a single year, and each can of soda
increases the odds of becoming obese, a JAMA study noted.

Sugar may well raise the risk of obesity directly, but the
association could be mediated by diabetes, metabolic syndrome, or
other diet and exercise habits associated with high-sugar diets.
And it's possible that soda is uniquely pernicious, above and
beyond other sugary foods.

"The complexity of our food supply and of dietary intake
behavior, and how diet relates to other behaviors, makes the
acquisition of clear and consistent scientific data on the topic
of specific dietary factors and obesity risk especially elusive,"
concluded one 2006 review. Still, a more recent review cautioned,
"we should avoid the trap of waiting for absolute proof before
allowing public health action to be taken."

7. Liver failure

Because of the unique way we metabolize fructose, it creates a
stress response in the liver that can exacerbate inflammation.
High doses of sugar can make the liver go into overdrive. That's
one reason excess fructose is a "key player" in the development
of nonalcoholic fatty liver disease, where fat accumulates in the
liver in the absence of alcohol abuse.

People with this diagnosis have been found to have almost double
the soda intake of the average person. Most don't experience any
complications and don't realize they have it. But in some people,
the accumulated fat can lead to scarring in the liver and
eventually progress to liver failure.

8. Pancreatic cancer

A handful of studies have found that high-sugar diets are
associated with a slightly elevated risk of pancreatic cancer,
one of the deadliest cancers. The link may be because high-sugar
diets are associated with obesity and diabetes, both of which
increase the likelihood someone will develop pancreatic cancer.
Still, one large study published in the International Journal of
Cancer disputed the link between increased sugar intake and
increased cancer risk, so more research is needed.

9. Kidney disease

The idea that a high-sugar diet — and too much soda in particular
— may be a risk factor for kidney disease is still just a
hypothesis, but there's some reason for concern. "Findings
suggest that sugary soda consumption may be associated with
kidney damage," concluded one study of 9,358 adults. (The association
emerged only in those drinking two or more sodas a day.) Rats fed
extremely high-sugar diets — consuming about 12 times the
percentage of sugar recommended in the WHO's new guidelines —
developed enlarged kidneys and a host of problems with regular
kidney function.

10. High blood pressure

Hypertension is usually associated with salty foods, not desserts
— but eating lots of added sugar has indeed been linked to high
blood pressure. In one study following 4,528 adults without a
history of hypertension, consuming 74 or more grams of sugar each
day was strongly associated with an elevated risk of high blood
pressure.

In another very small study following only 15 people, researchers
found that drinking 60 grams of fructose elicited a spike in
blood pressure two hours later. This response may be related to
the fact that digesting fructose produces uric acid, but — as one
meta-analysis of the data concluded — "longer and larger trials
are needed."

11. Heart disease

Heart disease may not get as much time in the spotlight as
diseases like cancer and AIDS, but it is in fact the number one cause of death in the United States.
While smoking and a sedentary lifestyle have long been
acknowledged as major risk factors. Conditions associated with
excess sugar consumption, like diabetes and being overweight, are
also already known risk factors for heart disease, and
recent research suggests that eating too much sugar might stack
the odds against your heart health — especially if you are a
woman.

In one study of rats with high blood pressure — which may offer
clues for further research but can't be directly extrapolated to
humans — heart failure came fastest when they were fed a diet
high in sugar (when compared to high-starch and high-fat diets).
And a CDC study of 11,733 adults concluded that there is "a
significant relationship between added sugar consumption and
increased risk for CVD [cardiovascular disease] mortality." When
participants got 17% to 21% of their daily calories from sugar,
they were 38% more likely to die from heart disease than those
who limited their calories from sugar to 8% of their total
intake.

12. Addiction

Doctors don't all agree the "food addiction" you read about in
diet books is a real thing, but there's recently been some
research indicating that the disorder might be possible in
humans. And there is evidence that rats can become dependent on
sugar, further supporting the idea that similar behavior might be
present in humans.

"In some circumstances, intermittent access to sugar can lead to
behavior and neurochemical changes that resemble the effects of a
substance of abuse," noted one study that found sugar-addled rats
displayed bingeing, craving, and withdrawal behaviors.

13. Cognitive decline

Obesity and diabetes are both risk factors for cognitive decline
and Alzheimer's, so it's no surprise that studies are beginning
to find a link between excess sugar and these cognitive
conditions. The reasons for a possible relationship between a
high-sugar diet and dementia later in life are still unclear.

Is there a direct dietary association? Is the real link between
diabetes and Alzheimer's only? One recent study found rats that
had diets high in fat and sugar could dull emotional arousal and
contribute to memory impairment. And another study in humans
found an association between diets high in high fructose corn
syrup and reduced performance in the hippocampus. Researchers are
currently investigating the many open questions, with some urging
caution until more evidence is gathered.

14. Nutritional deficiencies

If you're scarfing down lots of excess sugar, you're probably
skipping over the things you should be eating instead.
"High-sugar foods displace whole foods (eg, soft drinks displace
milk and juice consumption in children) and contribute to
nutritional deficiencies," noted a statement from the American Heart Association. In
a study of 568 10-year-olds, as sugar intake increased, intake of
essential nutrients decreased. And in a 1999 study, researchers
from the Department of Agriculture found that when people got 18%
or more of their calories from sugar, they had the lowest levels
of essentials like folate, calcium, iron, Vitamin A, and Vitamin
C.

15. Gout

Gout used to be considered a disease limited to the rich, but as
our diets have changed, this painful form of arthritis has become
more common across all sectors of society. Certain foods like organ meats and anchovies
that are associated with gout have high levels of something
called purines, and when your body breaks them down, it produces
uric acid. A buildup of uric acid is what often leads to gout.

But uric acid is also a byproduct of fructose metabolization, and
now newer research is suggesting that too much sugar could be a
risk factor for gout as well. "Consumption of sugar sweetened
soft drinks and fructose is strongly associated with an increased
risk of gout in men," concluded a 2008 study that tracked
thousands of patients for more than a decade.